The present invention relates to a window cleaning machine.
Major cities throughout the United States and throughout the world have numerous skyscrapers and other buildings which require cleaning on a periodic basis to ensure that the buildings are presentable to its residence, guests and visitors. To this end, maintenance personnel must constantly clean the interior and exterior surfaces of the building to maintain its cleanliness. One typical method of cleaning the exterior surfaces (e.g., windows, etc.) of the building is by supporting maintenance personnel on a roof top suspended scaffolding as the maintenance personnel manually cleans the windows and exterior surfaces of the building. Unfortunately, this exposes maintenance personnel to environmental conditions such as wind gusts thereby increasing the risk of injury to maintenance personnel. Additionally, maintenance personnel may fall from the suspended scaffolding to the ground resulting in serious injury or death. The U.S. department of health, and more particularly, the Occupational Safety & Health Administration (OSHA) estimates that 2.3 million construction workers work on scaffolding resulting in 4,500 scaffolding related injuries and 50 deaths.
Prior art window cleaning machines have been developed to automatically clean the exterior surfaces (e.g., window, etc.) of buildings, as shown in FIG. 1. These prior art window cleaning machines are safer than manually cleaning because manual cleaning requires maintenance personnel to clean the building windows while supported on a suspended scaffolding, as discussed above, whereas, in automatic cleaning, only the prior window cleaning machine and not maintenance personnel is supported over the side of the building to clean the exterior surfaces of the building.
Prior art window cleaning machines typically are hung over a side of the building via a boom or cantilever. They may be raised or lowered via cabling such that the prior art window cleaning machine may clean the entire vertical height of the building. Prior art window cleaning machines are also able to laterally traverse the side of the building such that the prior art window cleaning machines may clean the entire side of the building. The prior art window cleaning machines may have two speeds at which it laterally traverses the building side. The first speed provides gross lateral movement along the side of the building by rolling the boom along a track attached to the outer perimeter of the building's roof top. The second speed provides minuet lateral movement. This minuet movement is accomplished at the cleaning apparatus of the prior art window cleaning machine. In particular, the cleaning apparatus may comprise a cleaning apparatus and a frame. The cleaning surface may slide between a left side and a right side of the frame.
Unfortunately, prior art window cleaning machines are not stable. They are prone to tipping and the cleaning apparatus may apply uneven pressure on the exterior surface to be cleaned thereby decreasing the effectiveness of the prior art window cleaning machines and possibly breaking the window to be cleaned. In particular, the frame is hung from the boom by two cables. The two cables are attached to lateral distal ends of the frame. The frame then leans/rests on the exterior surface of the building such as the building window via four pads. These pads are typically positioned at the corners of the frame to stabilize the cleaning apparatus and frame as the cleaning apparatus is laterally traversed between the left and right sides of the frame. Since the weight of the cleaning apparatus may be substantial, the center of gravity of the cleaning apparatus may substantially shift the center of gravity of the prior art window cleaning machine as the cleaning apparatus is traversed between the left and right sides of the frame thereby destabilizing the prior art window cleaning machines.
In support thereof, the two left pads increasingly apply a force against the window as the cleaning apparatus traverses from the right side to the left side of the frame. Similarly, the two right pads increasingly apply a force against the window as the cleaning surface traverses from the left side to the right side of the frame. Such movement and uneven pressure applied to the window by the base may cause the prior art window cleaning machines to destabilize thereby tipping as wind gusts blow against the prior art cleaning apparatus. Additionally, the uneven pressure applied to the window by the pads may also vary the amount of pressure applied by the cleaning surface of the cleaning apparatus to the window thereby reducing the effectiveness of the prior art window cleaning machines. Also, if too much pressure is applied to the window via the pads, then the window may break under such excessive pressure.
Accordingly, there is a need in the art for an improved window cleaning machine.